Demountable brake lining



May 20, 1958 T. 1.. BONKOWSKI Re. 24,476

DEMOUNTABLE BRAKE LINING Original Filed Sept. 25, 1948 2 Sheets-Sheet lT-aHL L. Bum 0mm,

IN VEN TOR HTTUQNEVS y 20, 1953 T. L BONKOWSKI Re. 24,476

nmouumsm BRAKE LINING Original Filed Sept. 25, 1948 2 Sheets-Sheet 272-01% L. Bouzowsva,

INVENTOR.

BY g (@0100 i m HTTOENEVS Re. 24,476 Reissued May 20, 1958 United StatesPatentQfifice DEMOUNTABLE BRAKE LINING Teofil L. Bonkowski, Los Angeles,Calif.

Original No. 2,631,697, dated March 17, 1953, Serial No. 51,160,September 25, 1948. Application for reissue November 15, 1954, SerialNo. 469,067

2 Claims. (Cl. 188-234) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

My invention relates to demountable brake linings, that is, to brakelinings which may be secured to or removed from a brake shoe withoutremoval of the brake shoe from the vehicle. Included in the objects ofmy invention are:

First, to provide a demountable brake lining which is particularlysimple to install, remove, or replace without the use of special tools.

Second, to provide a demountable brake lining which may be so arrangedas to fit on a conventional brake shoe without changing or altering inany manner the construction of the brake shoe.

Third, to provide a demountable brake lining which eliminates the needof rivets and which may be so constructed that wear may proceed throughthe entire lining before metallic contact with the brake shoe can occur.

Fourth, to provide a demountable brake lining which is preformed to thecurvature of the brake shoe and may be so arranged that it is securedagainst both circumferential and axial displacement.

With the above and other objects in view, as may appear hereinafter,reference is directed to the accompanying drawings in which:

Fig. 1 is a substantially diagrammatical view of a vehicle brake showingone form of my demountable brake lining in position on the brake shoes;

Fig. 2 is an enlarged view of a brake shoe, the view being taken fromthe radially inner side thereof and showing the manner in which one formof my demountable brake lining is secured thereto;

Fig. 3 is a transverse sectional view, taken through 3-3 of Fig. 2;

Fig. 4 is a side view of a brake shoe using a modified form of mydemountable brake lining thereon;

Fig. 5 is a fragmentary view from the radially inner side of the brakeshoe shown in Fig. 4;

Fig. 6 is a fragmentary perspective view of the brake shoe and liningshown in Figs. 4 and 5, the parts being separated to illustrate themanner in which they are assembled;

Fig. 7 is a fragmentary perspective view of a further modified form ofmy brake lining shown in spaced relation to a brake shoe;

Fig. 8 is a fragmentary perspective view of a further 1 modified form ofbrake shoe with the lining shown in the process of assembly thereon;

Fig. 9 is a fragmentary view showing the radially inner side of thebrake shoe and lining depicted in Figure 8; and

Fig. 10 is a fragmentary transverse sectional view through 1010 of Fig.9.

Reference is first directed to Figs. 1, 2, and 3. The structure hereinillustrated is preferred for the reason that it may be adapted to use ona conventional brake shoe.

The conventional brake includes a pair of brake shoes A mounted within abrake drum B. The brake shoes are connected at one end by a suitablelink C. At the other end a hydraulic cylinder D is interposed betweenthe brake shoes so they may be expanded into contact with the brakedrum. Each brake shoe is arcuate in form and T-shaped in cross section.

In the construction shown in Figs. 1, 2, and 3 a backing member 1 isprovided which is formed of sheet metal and curved to conform to andoverlie the brake shoe. One side of the backing member is folded to forman arcuate stiffening rib and locking channel or lip 2. The channel isadapted to hook over the axially inner side of the brake shoe. Theopposite or outer edge of the backing member is provided with a set oftabs 3 which are initially straight as indicated by broken lines inFigs. 2 and 3, but which, after placement of the backing member on thebrake shoe are adapted to be bent over so as to engage the correspondingaxial margin of the. brake shoe. The circumferential extremities of thebacking member are provided with end lugs 4 which overlie thecorresponding extremities or ends of the brake shoe.

The backing member 1 is covered by a brake. lining 5 which is preferablycemented thereto as indicated by 6. Such lining 5 may be a conventionalmolded lining having the usual substantially rigid inherently arcuateshape. By this arrangement all rivets or other means which must protrudeinto the lining are eliminated so that the lining may wear virtually itsentire thickness before replacement is necessary or beforemetal-to-metal contact occurs. In addition, the backing member may havetransverse ridges and grooves and the brake lining molded accordingly.

My demountable brake lining is employed as follows:

To install the brake lining, it is merely necessary to remove the wheeland brake drum and expose the brake shoes, assuming, of course, that theshoes are not equipped with conventional brake lining. The backingmember is then slipped over the brake shoe from the exposed oraccessible side thereof with the channel 2 towards the inner axial sideof the brake shoe until such channel hooks over and engages the brakeshoe. The tabs 3 are then bent over to grip the axially outer oraccessible side of the brake shoe. To remove, it is merely necessary tobend these tabs 3 to their initial position and unhook the backingmember from the brake shoe. It thus will be seen that a minimum amountof work is necessary to install or replace my demountable brake liningand that no special tools are required.

The channel member 2 greatly stiifens the backing member so as to reducethe possibility that the relatively brittle brake lining may be brokenor torn loose during handling or shipment, as might be the case if thebacking member should flex.

Reference is now directed to Figs. 4, 5, and 6. In this construction anotherwise conventional brake shoe 10 is, modified by providing recessesor notches 11 at spaced points along the axially inner and axially outermargins of the brake shoe. A backing plate 12 is provided which isformed of sheet metal, as in the first described case. Side lugs 13 arebent radially inwardly from the backing plate 12. This may be done priorto installing the backing plate on the shoe as shown in Fig.

The lugs preferably in- I 3 it is merely necessary to spring the backingplate Over the brake shoe and guide the lugs 13 into the notches 11 andthen move the backing plate arcuately a slight distance so that thetongues 14 underlie the corresponding extremities of the notches 11, orto bend the lugs as in the first described structure. Locking tabs 16formed by slitting the backing plate adjacent the lugs 13 may be bentinto the notches 11 behind the lugs to prevent accidental disengagement.

It should be Observed that one or bath margins of the brake shoe Aassociated with the first described structure may be provided withcircumferential interlocking means or notches, such as the notches 11 ofthe structure shown in Figs. 4, 5, and 6, and the tabs 3 may be benttherein to effect circumferential locking of the backing plate on thebrake shoe.

Reference is now directed to Fig. 7. This construction is adapted to beemployed on the conventional brake shoe A or on the special brake shoe10, This construction includes a lining 21 in which is molded insertstrips 22 which are disposed crosswise or axially and terminate at tabends 23 which protrude from the lining 21 and are adapted to be foldedover the margins of the brake shoe in the manner of the tabs 2 and 3 ofthe first described structure. Additional tabs may extendcircumferentially from the extremities of the lining 21 to perform thefunction of the end lugs 4 of the first described structure.

Reference is now directed to Figs. 8, 9, and 10. The

structure here shown involves a special brake shoe 31' which differsfrom the conventional in that it is provided with pairs of tapered slots32. A molded lining 33 is employed which includes integral taperedbosses 34 adapted to fit the tapered slots 32. The bosses 34 preferablyare provided with small side ribs 35 so as to interlock with the marginsof the tapered slots 32.

At the larger end of one or more tapered bosses 34, the lining isprovided with a keeper opening 36 which receives a keeper plug 37 formedof brake lining material. The keeper plug is adapted to be inserted inthe keeper opening and extends into the tapered slot 32 to preventwithdrawal of the bosses 34. The keeper plug is provided with a cotterpin hole 38 to receive a cotter pin 39 employed to prevent removal ofthe keeper plug.

Assembly of the structure shown in Figs. 8, 9, and 10 is as follows:

The molded brake-lining 33 is placed over the. brake shoe. and thebosses 34 are pressed into the slots 32.

The lining is then moved circumferentially in the direction of thearrowin Fig. 8 until the bosses interlock with the slots, whereupon the.keeper plug, or plugs, is inserted and the cotter pin 39 placed to.prevent withdrawal of the keeper plug.

Having fully described my invention, it is to be understood that I donot wish to be limited to the details herein set forth, but my inventionis of the full scope of the appended claims.

I claim:

1. A demountable brake lining for brake shoes of arcuate form,comprising: an arcuate sheet metal back- 3 ing plate having a radius ofcurvature substantially equal to that of .the outer surface of the brakeshoe, one margin only of said arcuate backing plate having a continuouscircumferentially extending, radially inwardly directed flange, saidflange terminating along its radially inner edge in a continuous arcuatelip extending away from said flange to form with said backing plate anarcuate trough, the opposite arcuate margin of said backing plate havinga plurality of spaced tabs extending axially away from said opp sitearcuate margin, and a brake lining having a substantially rigidinherently arcuate shape cemented to said backing plate.

2. A demountable brake lining as set forth in claim 1, wherein: thecircumferential extremities of said backing plate have tabs adapted tobe folded over the ends of said brake shoe to resist circumferentialdisplacement of said backing plate and brake lining. I g

[3. Ademountable brake lining as set forth in claim 1, wherein: saidbrake shoe is provided with a series of recesses along one arcuatemarginv to receive said tabs,

'- the circumferential extremities of said recesses cooperating with thecircumferential edges of said tabs to resist circumferentialdisplacement of said backing plate and brake lining] References Cited inthe file of this patent or the original patent UNITED STATES PATENTS1,225,555 Achtmeyer May 8, 1917 1,537,233 Hartman May 12, 1925 1,542,185Sweet June 16, 1925 1,620,030 Krieg' Mar. 8, 1927 1,772,639 Slade Aug.12, 1930 1,856,812 Jirka May 3, 1932 1,903,723 Palmer Apr. 11, 19331,950,260 Nelson Mar. 6, 1934 2,027,823 Hoffman Jan. 14, 1936 2,153,341Rutfino Apr. 4, 1939 2,326,300 Kraft Aug. 10, 1943 2,598,545 House May27, 1952 FOREIGN PATENTS 898,821 France May 8, 1945 Italy June. 19,

